Belgian patent application No. 2013/0015 provides a solution to this, whereby a lock plate is slidably placed in a groove in the top profile from the side, where the groove is open and secured by means of a connecting piece that is slid in a similar groove in the side profile of the leaf.
However, the manufacturing tolerances of the leaf and the outer frame mean that the positions of the lock and the lock plate sometimes poorly correspond, so that either a pin or pins of the lock do not enter into the lock plate, such that the lock does not work, or there is a greater than desired play between the pins and the lock plate.